
3-Way Valve Saunier Duval ThemaClassic C24E Ref. S1020800
Three-way valve Saunier Duval ThemaClassic C24E Ref. S1020800, a component that allows the alternation of water flow between the heating circuit and the domestic hot water circuit. If it fails, you will notice that you have hot water but no heating, or vice versa, and there may even be a mixing of both circuits. This valve is compatible with models such as ThemaClassic F 24 E, ThemaClassic C 24 E, among others. It is advisable to replace it when you observe these symptoms or when the fault code F14 is activated, which indicates that the heating temperature exceeds 95 °C.
VAT included
Consult via WhatsAppSaunier Duval boilers compatible with reference S1020800
3-way valve with reference S1020800. 16 verified compatibilities: ThemaClassic F 24 E and ThemaClassic C 24 E.
Proven compatibility
| Boiler model | Family | Verification |
|---|---|---|
| Saunier Duval ThemaClassic F 24 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic C 24 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic C 24 EV | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic F 25 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic C 25 E | ThemaClassic | Contrasted |
| Saunier Duval ThemaClassic C 25 EV | ThemaClassic | Contrasted |
| Saunier Duval Thematek F 24 E | Thematek | Contrasted |
| Saunier Duval Thematek C 24 E | Thematek | Contrasted |
| Saunier Duval Thematek C 24 EV | Thematek | Contrasted |
| Saunier Duval Thematek C 18 E | Thematek | Contrasted |
| Saunier Duval Thematek C 18 EV | Thematek | Contrasted |
| Saunier Duval Thematek S F 24 E | Thematek | Contrasted |
| Saunier Duval Thematek S C 24 E | Thematek | Contrasted |
| Saunier Duval Thema F 24 E | Thema | Contrasted |
| Saunier Duval Thema C 24 E | Thema | Contrasted |
| Saunier Duval Thema C 24 EV | Thema | Contrasted |
Can't see your model or have questions? The printed reference takes precedence. How to check it · Send us a photo via WhatsApp.
How to check if ref. S1020800 is the part for your boiler
What determines it is not the boiler model, but the reference printed on the part you already have installed.
- Find the reference printed on the installed part and check whether it matches the catalogue reference S1020800. If it is not visible, do not identify the part from its shape alone.
- Check the full boiler model on its data plate and look for it in the model associations on this page.
- Compare the connections and physical body with the original part before installation.
- If anything is unclear, send us a photo of the marking via WhatsApp before placing your order.
Symptoms and faults that the S1020800 three-way valve resolves.
The 3-way valve diverts water between heating and domestic hot water. These are the typical symptoms and what to do:
Common symptoms and faults
- 01
The boiler takes a long time or fails to switch between heating and domestic hot water.
Cause: The internal mechanism of the valve is worn out or seized, and the motor cannot move it smoothly.
Check if the fault occurs always or only sometimes: if it is intermittent, it could be the motor overheating before the gas valve.
- 02
Water is leaking right at the body of the three-way valve.
Cause: The gasket or the valve stem has worn out and no longer seals the water passage.
Dry the area well and check again after a while of operation to confirm that the leak is coming from the body of the gas valve and not from a nearby fitting.
- 03
Limescale or white residue is visible around the valve.
Cause: A small and continuous leak leaves lime marks when it dries, indicating that the internal gasket no longer seals.
If you see dry scale but water is not dripping right now, confirm that there is an intermittent leak that should be resolved.
- 04
The boiler switches circuits with a noticeable delay compared to before.
Cause: The progressive wear of the mechanism causes the motor to require more time or more force to move the shutter.
Compare how long it takes to change now compared to when the boiler was new, to assess if the wear is advanced.
Fault codes from Saunier Duval that this spare part resolves.
| Code | Fault | Diagnosis and solution |
|---|---|---|
| F14 | Heating temperature > 95 °C (temperature limiter). | If the 3-way valve (S1020800) gets stuck or does not switch, the boiler remains in the heating circuit during DHW demand, causing overheating and F14; verify by forcing DHW/heating demand and checking that the actuator moves the spindle and that the 3-way valve is not seized/calcified. |
These symptoms can have more than one cause. If your boiler displays a fault code, send it to us via WhatsApp along with a photo of the labeling, and we'll tell you if this is the part.
Data sheet for the Saunier Duval S1020800 three-way valve.
- Catalogue reference
- S1020800
- Brand
- Saunier Duval
- Type of part
- 3-way valves
- Units in stock
- 1 unit
- Status
- Refurbished
- Warranty
- 1 year
- Shipping
- 1-2 business days
- Return
- 14 days
Data read on the part and in the manufacturer's documentation
What we have not been able to verify does not appear here.
- Code engraved on the part
- 591958












